Pallet fork contacting and indexing means for electric watch



Oct. 23, 1962 H. s. DETWILER 3,059,413

PALLET FORK CONTACTING AND INDEXING MEANS FOR ELECTRIC WATCH Filed Jan. 2, 1959 2 Sheets-Sheet 1 FIG. I.

INVENTQR. Harry 8.0efw1/er mama 4 Oct. 23, 1962' H. s. DETWILER 3,059,413

PALLET FORK CONTACTING AND INDEXING MEANS FOR ELECTRIC WATCH Filed Jan. 2. 1959 2 Sheets-Sheet 2 E o co N N 0 cu N INVENTOR: Harry 5. Defwller United States Patent PALLET FORK CONTACTING AND INDEXING MEANS FOR ELECTRIC WATCH Harry S. Detwiler, Lancaster, Pa., assignor to Hamilton Watch Company, Lancaster, Pa., a corporation of Pennsylvania Filed Jan. 2, 1959, Ser. No. 784,596

11 Claims. (Cl. 58-28) This invention relates to battery operated electric watches and more particularly relates to the contact, indexing and overbank preventing arrangement used in such watches.

In assignees copending application Serial No. 409,934, filed February 12, 1954, and now Patent No. 2,888,797, there is disclosed a battery operated electric watch wherein the balance wheel carries a coil adapted to cooperate with permanent magnets mounted on the pillar plate of the watch to provide impulsing to the balance wheel in order to sustain it in oscillation.

This coil is energized periodically through a contact system which is carried by the balance wheel assembly and which provides connections to the watch contained battery. The balance wheel assembly further carries a means for driving an index wheel or gear so as to impart motion to the train of the watch. In order to prevent overbanking, various known expedients have been resorted to.

In the foregoing type of watch, the contact, index and overbank mechanisms are distinct and separate and require rather precise alignment in relation to one another in order to assure proper operation of the watch. This alignment must initially be performed at the factory and thereby adds a not insubstantial cost item to the price of the watch.

According to the present invention, it has now been found that through the use of a unique mechanism, it is possible to combine the contact, index and overbank mechanisms in such a manner that when the overall system, is assembled, no final adjustment is necessary because all of the parts are self-aligning.

It is accordingly a primary object of the present invention to provide a contact, index and overbank mechanism for a battery operated electric watch which is simple in construction and which, when assembled, requires no final adjustment.

It is another object of the invention to provide in a battery operated electric watch a unitary contact, index and overbank prevention system which is self-aligning.

It is still another object of the invention to provide in a battery operated electric watch a unitary contact, index and overbank preventing system which is self-aligning and eliminates process steps in the manufacture of such watches.

These and further objects and advantages of the invention will become more apparent upon reference to the following specification and claims and appended drawings wherein:

FIGURE 1 is a plan view showing a contact, index and overbank prevention system constructed according to the present invention; and

FIGURE 2 is a vertical section taken along the line 22 of FIGURE 1.

Referring more particularly to the figures of the drawing, a balance staff carrying a balance wheel 12 is mounted in a pillar plate 14 in a conventional manner. The balance staff also carries an insulating index roller 16 in which a high conductivity contact member 18 is mounted. The contact member '18 may be of any high conductivity metal but is preferably a precious metal such as gold alloy. This contact pin is connected by 3,059,413 Patented Oct. 23, 1962 means of a connection 20 to a coil carried by the balance wheel as is described in detail in assignees aforementioned copending application. The other terminal of the coil is connected to the hairspring and thence to the battery circuit. The index roller 16 is attached to a sleeve 22 which also carries a safety roller 24'having a crescent shaped cutaway portion 26 as seen in FIGURE 1.

A pallet 28 is pivoted to the pillar plate at 30 and is provided with a forked end 32 which surrounds the contact and index pin 18 in the position shown in FIGURE 1. A guard pin 34 is attached to the bottom of the forked end 32 of the pallet 28 and is adapted to enter the crescent shaped cutaway portion 26 of the safety roller 24. A pair of magnetic banking pins 36 and 38 are mounted on either side of the forked end of the pallet in insulating sleeves 40.

The other end of the pallet 28 is provided with arms- 42 and 44 carrying pins 46 and 48 at the ends thereof. The upper pin 46 in FIGURE 1 is formed of an insulating material, preferably a jewel such as sapphire. The lower pin 48 is formed of a wear resistant, conductive metal such as steel. The pins 46 and 48 are adapted to engage the saw tooth shaped teeth of an index wheel 52 journaled in the pillar plate on a shaft 54. This index wheel is geared to the watch train, not shown. The index wheel 52 is mounted on the staff 54 on an insulated bushing 55 as is seen in FIGURE 2 in order to maintain the integrity of the electrical circuit.

Resiliently urged against the teeth 50 of the index gear 52 is the end 56 of a stabilizer spring 58 mounted on an insulating block 60. The spring end 56 has an arcuate inner edge 62 containing a pair of notches 64 and 66 which are adapted to engage the ends of the teeth 50 of the index wheel 52. The other end of the stabilizer spring terminates in a slotted portion 68 which is oriented I on the block 60 by means of a pair of pins 70 and '72 and which is secured in position by means of a screw 74. The underside of the screw 74 makes contact with a connector 76 which is connected to the battery in the watch. The block 60 is itself secured to the pillar plate in any suitable manner such as by the pair of screws 78 and 80.

In operation, as the balance staff and index roller 16 oscillate in a counterclockwise direction, the index and contact pin 18 makes mechanical engagement and elec trical contact with the inner surface of the forked end 32 of the pallet 28 and moves the pallet in a clockwise direction. This brings the metal pin 48 into engagement with the teeth 50 of the index wheel 52, thereby completing a circuit to the coil carried by the balance wheel through the index wheel, stabilizer spring 58 and connection 76. This causes the coil to be impulsed to move the balance staff further in a counterclockwise direction, whereupon the contact and index pin 18 clears the forked end 32 of the pallet 28.

' The banking pins 36 and 38 are of magnetic material and cause the pallet to finish its action after it has moved the index wheel through its specific arc and retains the pallet as the balance staff completes its cycle of oscillation.- If the balance wheel overbanks, that is, rotates through an angle of excess amplitude, the contact and index pin 18 strikes the outside contour of the forked end of the pallet, which is held against the banking pin 36 to prevent further oscillation.

As the balance staff and associated index roller 16 rotates in the clockwise direction, the pallet is caused to rotate counterclockwise thereby bringing the insulated pin 46 into engagement with the teeth of the index wheel. This does not complete a circuit to the coil but does carry out the indexing function as well as provide for overbank prevention. The outside surface of the forked end of the pallet is insulated by any suitable coating in order to prevent contact from being made at the time that the contact and index pin might strike the pallet during overbank prevention.

The pins 46-and 48 actuate the index wheel 52, so that, it turns in ajcounterclockwise direction only and moves until the stabilizer spring reaches the tip of the next tooth. At this time the stabilizer spring takes over the rotation of the index wheel until the spring seats itself on the next tooth automatically positioning the index wheel for the next pin on the pallet.

It will be apparent from the. foregoing that by utilizing the arrangement of this invention, the functions of the contact system, index system and overbank prevention system are combined in a unitary mechanism which possesses the following advantages: Indexing is positive to thereby provide a smooth running second hand. A definite contact time is established for energizing the coil Without the need for contact adjustment. The overbank mechanism is simplified and is provided as a part of the contact and indexing mechanism. Through the use of a 2 pallet it is possible to utilize a conventional. design roller,

jewel pin, forked slot and banking pin. Thinner'watch construction is possible and final adjustment is eliminated. The invention may .beembodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respectsv as illustrative and not re strictive, the, scope. of the invention being indicated by the appended claims rather than by the foregoing descrip tion, and all changes which come Within the meaning and range of equivalency of the claims are therefore intended to be-embraced therein. 9

States Letters Patent is:'

1. In a battery operated electric Watch having a balance staff carrying one element of a magnetic impulsing system and having the other elementlof said system carried by the watch frame, one of said elements adapted tobe periodically energized by said battery,and having a traindriven-by an index Wheel, the improvement comprising; a pallet. mounted .on said frame for rocking movement and'having one end adapted to mechanically engage said indexwheel during said rocking movement to advance said index Wheel in one direction; means on said balance stafr" for engaging the other end of said pallet to impart said rocking movement as said balance staff oscillates, said pallet rocking in' alternate directions upon oscillation of said balance staff in alternate directions, said last named means beinga'rrang'ed to provide electrical contact between said pallet and one of said elements during rocking motion of said pallet, said end of said pallet adapted to engage said index wheel being so arranged as to make electrical contact therewith as said pallet rocks in one direction only; and magnetic means cooperating with said pallet to maintain said one end in contact with said index wheel until separated therefrom upon oscillation of said balance staif in a direction op posite to that causing said pallet to rock in said one direction.

2. A battery operated electric watch as set out in claim 1 wherein said one end of said pallet is bifurcated to form a pair of arms, each of said arms carrying a pin for engagement with said index Wheel, one of said pins being electrically conducting and the other being electrically insulating.

3. A battery operated electric watch as set out in claim 2 wherein said other end of said pallet is forked and co operates with a conducting contact member and index pin carried by said balance staff.

4. A battery operated electric watch as set out in claim 3including a stabilizer spring engaging said index wheel and establishing electricalcontact from said stabilizer through said index Wheel and pallet to said contact member when said contact member engages said forked end of said pallet.

5. A battery operated electric watch as set out in claim 1 wherein said other end of said pallet is forked and cooperates With aconducting contact member and index pin carried by said balance staff.

6. A battery operated electric watch as set out in claim 5 including a stabilizer spring engaging said index wheel and establishing electrical contact from said stabilizer through said index wheelfand pallet to said contact member when said contact member engages said forked end of said pallet.

7. A battery operated electric watch as defined in claim 1 wherein said. magnetic means cooperates with said other end of said pallet to'p're'vent multiple indexing and contacting. f

i 8. A battery operated electric watch having a balance staff carrying oneelernent ofja magnetic impulsingsys tern and having theother element of said slystern carried:

by the watch frame, one .of saidelements'beingadapted to be periodically energized by said batteryrabalance- I wheel mounted on said balance 'staifi'a train; an index wheel for driving said train; means mounted on said frame for rocking movement and having one end adapted to mechanically engage ,said index wheel during said rocking movement to advance said index wheel in one direction; means on said balance stafffor periodically engaging the other end .of said mounted means to impart said rocking movement as said balance staff oscillates, said last mentioned means being arranged to'p'ro vide electrical contact between said mounted means and one of said elements during rocking .motion of said mounted means, said one end of said mounted means being so arranged as to make electrical contact with said index wheel as said mounted means rocks in one direction only.

9. The Watch defined in claim 8 wherein said one end of said mounted means carries two pins, one of which is electrically conductive for engagement with said index wheelas said mounted means rocks in said one direction, the other of which is electrically insulated for en- 'gagement with said index Wheel as said mounted means mounted on said frame and cooperating with said other end of said mounted means to restrict said balance staff from multiple indexing and contacting.

References Cited in the file of this patent UNITED STATES PATENTS 

